This invention relates to a brake of the general kind in which a friction element is movable by hydraulic actuating means into braking engagement with a rotary braking member.
Conventional hydraulically operated braking systems have hitherto been considered unsuitable for operation as parking brakes because the possibility of leaks, albeit minute, occurring during the parking brake mode leads to a risk of the braking force becoming insufficient to maintain a vehicle stationary, particularly on an incline. Because of the possibly disastrous consequences of this, especially with an unattended vehicle, hydraulically operated brakes usually incorporate an independent mechanical linkage for parking brake purposes, in order to provide the necessary degree of security.